There are many ways to skin a cat so, here is mine. I start by cleaning the body in HOT dawn liquid soap water overnight. This should get the mold grease off the model without harming the plastic. Then rinse with water making sure not to leave big drops on top of the body while it air dries.
Next, prime with Tamiya primer "second choice is Dupli-color Primer sealer found at Auto-zone" as it is the closest to Tamiya I have found. Dupli-color is just slightly thicker but it is about 90% like Tamiya.
Then, check body for flaws and dust spots and sand lightly with 1000 grit or better sand paper. Wash it to get dusts off and paint. If you want you can go one step better and try to polish your primer for the best possible results.
Mark